Reinforced concrete structures are usually made in a number of stages including construction of the form work, tying the steel and pouring the concrete. In order to maintain a structural link between say, foundations and walls or floors, it is usual to "tie" reinforcing bars between the structures so that the bars are common to both structures. This invariably results in the bars being exposed for a period of time which presents an occupational hazard to workers who may fall on the bars and suffers serious injury including impalement.